The invention described herein relates to a method for producing rapid pH changes in solution and more particularly to a method wherein the rapid pH change is produced by irradiating the solution with an intense flux of light of the desired frequency. It is a result of a contract with the Department of Energy.
In terms of both the chemical insight gained and the predictive power provided, the concept of acids and bases must surely be one of the most general in all of chemistry. According to the Bronsted-Lowry definition, an acid is a compound which is a proton donor, whereas a base accepts protons from solution. For acids and bases in protic solvents, acid-base chemistry becomes the chemistry of the proton. Since the proton has no electron cloud, its ionic size is about 10.sup.-6 nm, making it unique among cations, the rest of which are at least 10.sup.5 times larger. Consequently, the proton is very reactive, since it can closely approach and highly polarize molecules and chemical bonds.
It is not surprising therefore that the majority of solution phase reactions, including most reactions of biological importance, are either acid- or base-catalyzed. Unfortunately, the exceedingly rapid rates typical of most proton transfer reactions make it quite diffucult to study such acid-base chemistry by conventional techniques. While picosecond laser spectroscopy provides a general method for the study of proton-transfer reactions, it would be most useful to have some means of controlling the rapid initiation of such reactions in order to properly understand their mechanisms and kinetics.
Since the rate of proton transfer reactions is obviously influenced by the number of protons or hydrogen ions present in the solution, it is apparent that a means of rapidly changing the hydrogen ion content of the solution would offer a general, widely applicable method for rapid initiation of solution phase chemistry. A convenient means of expressing hydrogen ion concentration without the use of negative exponents is the pH scale. A rapid change in pH then is a measure of a rapid change in hydrogen ion (proton) concentration.
Accordingly, it is a general object of the invention to provide a method for rapidly changing the pH of a solution.
Another object is to provide such rapid pH change without the use of additional reagents.
Yet another object of the invention is to provide a degree of control over the amount of the pH change which occurs in the solution.
Other objects, advantages and novel features of the invention will become apparent to those skilled in the art upon examination of the following detailed description of a preferred embodiment of the invention and the accompanying drawings.